Molecular confirmation and interrelationship of phytoplasmas associated with diseases of palms in South India

Suspected phytoplasma symptoms of yellowing of inner whorl of leaves and rotting of spear in oil palm, yellowing of outer whorl of leaves in arecanut and flaccidity, yellowing and necrosis of crown leaves in coconut were observed in Kerala and Karnataka states of India. Phytoplasma presence in symptomatic oil palm, arecanut and coconut was confirmed by nested PCR assays with phytoplasma specific universal primers. 16Sr DNA sequence analysis and phylogenetic relationship studies confirmed the presence of 16SrXI group phytoplasmas in spear rot disease of oil palm from Kollam and Wayanad districts and in yellow leaf disease of arecanut from Wayanad district of Kerala. However, 16SrXIV group phytoplasmas were identified from root (wilt) disease of coconut from Kollam district of Kerala and yellow leaf disease of arecanut from Sullia of Dakshina Kannada district of Karnataka. This is the first report of association of 16SrXIV group phytoplasma with root (wilt) disease of coconut and yellow leaf disease of arecanut. These studies indicated the possible involvement of more than one group of phytoplasmas (16SrXI and 16SrXIV) in palm diseases in South India.